I just purchased a HD 6950 and installed into the case today. Problem is that computer won't boot (just a flash of LEDs in case and then nothing) with the cables to the three monitors plugged in. If I remove the cables, it boots fine. At that point, I can plug in the cables and all is well. It will restart no problem but a cold start and only frustration and anger. This card is replacing a HD 5870 that was crashing (BSOD) and I have not had any problems like this before. I built this machine, so I am certain that the other components are operating fine. Power supply is 1200W with plenty of power to spare.
Please throw some ideas that I can try to allow this computer to boot with cables plugged in.
Note: I have three monitors, but only two are being used due to me not realizing that I ordered passive DP cables. I have active cable ordered. This could be problem. I also suspect a short somewhere on the card (that would suck) and I will have to send it back.
my initial thought was your powersupply but with 1200w you can rule that out im pretty sure. Are you able to boot it successfully with 1 or 2 monitors plugged in or does it fail to boot with any plugged in?
I just discovered something this morning. It won't boot if the Mini display port cable is plugged in. It will boot with the DVI-D and HDMI plugged in. I'm guessing it has something to do with display port cable being passive. New active cable here Friday.